Trials Evolution is an extension of the sort of game I’m accustomed to playing in my browser, composed in Flash and simple enough in concept to be controlled with only a trio or quartet of keys at most. The idea is that physics are fun and driving motorcycles is more fun, so combining them with hazardous obstacle courses that demand the total sum of your physics-defying, high-flying, acrobatic acumen to surmount must be super fun.

Well, they’re right. It really is super fun. Or it was, anyway, since Trials Evolution came out in April. Trials HD, to which it was a sequel, hit way back in 2009. Now we’re looking at the game’s second expansion pack, Riders of Doom, so titled to cash in on the fervor that had surrounded the December 21, 2012 apocalypse hullabaloo that had the Internet cursing a long-passed Native American culture and their truncated calendar.

The world didn’t end, though, and Riders of Doom probably wouldn’t have been how I’d have chosen to see it out, anyway. That isn’t to say it isn’t a fun addition to the core experience that Trials Evolution provides, but if you’re going to pay five dollars for an expansion, a full third of what the original experience cost, you’re going to expect something that makes you feel like you got another sizable chunk of the experience.

I guess, in the strictest terms, Riders of Doom delivers exactly that. More tracks for those at all levels of skill, more skill challenges with unique and often wacky objectives, some of which don’t even seem to touch on the core game, and more parts for building one’s dream (or nightmare) track, which can then be unleashed on the unsuspecting masses.

In the new tracks, nothing of the core experience has been altered. You’re still manipulating your rider’s balance on his bike as he speeds along turbulent terrain, surmounting obstacles with careful shifts in his weight, hurtling from perilous jumps over dramatic distances. It can often prove positively eye-catching, and some of the new tracks (such as one set in a city in the sky) are positively breathtaking. There’s also one that serves as a belated Halloween celebration, and a third that involves UFOs. It all smacks of a missed opportunity, though. Riders of Doom has a few stages that evoke that “end of the world” sensation, playing on tropes thereof, but it doesn’t really serve as a unifying theme. The levels are more a hodgepodge of different flavors and textures that are certainly of high quality, but would have been more interesting if they in some way formed a progressive narrative. The difficulty, on the other hand, follows a progression much like that of the base game, though far sharper.

The stages run the gamut in challenge from the very simplest, pretty much easing one back in after a long absence from the game, to controller-chucking hard, with painfully precise jumps stacked atop one another with nary a checkpoint in sight. Personally, I think the game as a whole is at its best when its tracks strike a balance between spectacle and challenge. There’s little fun to be had trying the exact same jump 30 times just to get it right once in isolation, but it’s an absolute blast trying to chain together a sequence of simpler maneuvers in a single, faultless trial. I’m sure there are Trials hardcore who disagree with me, though, and are able to flawlessly bunny-hop from platform to platform.

Skill challenges are where the designers behind Riders of Doom went nuts and pulled out all the stops. While the main levels are enjoyable, they don’t really diverge from what has defined the Trials experience since day one. That skill challenges, meanwhile, don’t stop with variations on the basic motorcycle-navigating-the-track theme, but include one-off experiences such as motorcycle shot put, jumping challenges, a jet-pack-based stacking game, a Marble Madness-esque ball-rolling maze, and a slalom-esque rocket race with controls ripped from Asteroid.